The U.S. East Coast began a whiplash-inducing stretch of weather Wednesday with a deluge of rain, rapid snowmelt and powerful gusts, creating dangerous conditions, due in part to an atmospheric river and developing bomb cyclone.

Parts of the U.S. East Coast and Atlantic Canada are preparing for the impact of an atmospheric river, a weather phenomenon that is more commonly associated with the West Coast.

Places like western Maine could see freezing rain, downpours, unseasonably high temperatures and damaging winds — all in the span of a day.